Apparatus for securing the bolts of the reactor pressure vessel head to the reactor pressure vessel

ABSTRACT

Apparatus securing a locking bolt of a pressure head to a reactor pressure vessel in which the pressure head flange is urged in one direction and the bolt is tensioned in an opposite direction to reduce the interfacing force between confronting walls of a nut securing the locking bolt and the pressure head flange, while an operator tightens the nut against the pressure head flange. For tensioning the bolt, a cylindrical force transmitting member has its lower end threaded for engagement with the locking bolt and it upper end threaded, but without any pitch, to receive in threaded engagement a puller or lifter rod similarly threaded. The force transmitting member is split axially so that its halves can be displaced radially to facilitate the retaining of the lifter rod in threaded engagement therewith, while rotating the force transmitting member for adjustable threaded engagement with the locking bolt without rotating the puller rod. Axially movable retaining sleeves surround the split force transmitting member for at times to permit separation thereof to retain the lifted rod in threaded engagement therewith while rotating the force transmitting member for adjustable threaded engagement with the locking bolt without rotating the puller rod, and at other times securing the force transmitting member in locking engagement with the lifter rod for movement therewith. For urging the flange in the one direction a force is transmitted through columns and a connector sleeve for application to the pressure head flange. A suitable hydraulic system with pistons initiates the transmitted forces in each direction.

United States Patent 1191 Jones 1 51 Mar. 27, 1973 Cecil R. Jones, SanJose, Calif.

Transfer Systems Incorporated, New York, N.Y.

Filed: June 1, 1971 Appl. No.: 148,617

Inventor:

Assignee:

US. Cl ..8l/57.38, 254/29 A Int. Cl. ..B25b 29/02 Field ofSearch....8l/57.38, 57.36, 57.22, 57.25, 81/5724; 254/29 A [56]References Cited UNITED STATES PATENTS Biach ..81/57.38 Tucker......8l/57.38 Biach ..8l/57.38 Kreokel (it al. ..8 1/5736 PrimaryExaminer.lames L. Jones, Jr. AttorneyJack Oisher [5 7 1 ABSTRACT to areactor pressure vessel in which the pressure head flange is urged inone direction and the bolt is tensioned in an opposite direction toreduce the interfacing force between confronting walls of a nut securingthe locking bolt and the pressure head flange, while an operatortightens the nut against the pressure head flange. For t'ensioning thebolt, a cylindrical force transmitting member has its lower end threadedfor engagement with the locking bolt and it upper end threaded, butwithout any pitch, to receive in threaded engagement a puller or lifterrod similarly threaded. The force transmitting member is split axiallyso that its halves can be displaced radially to facilitate the retainingof the lifter rod in threaded engagement 1 therewith, while rotating theforce transmitting member for adjustable threaded engagement with thelocking bolt without rotating the puller rod. Axia'lly movable retainingsleeves surround the split force transmitting member for at times topermit separation thereof to retain the lifted rod in threadedengagement therewith while rotating the force transmitting member foradjustable threaded engagement with the locking bolt without rotatingthe puller rod, and at other times securing the force transmittingmember in locking engagement with the lifter rod for movement therewith.For urging the flange in the one direction a force is transmittedthrough columns and a connector sleeve for application to the pressurehead flange. A suitable hydraulic system with pistons initiates thetransmitted forces in each direction. 1

Apparatus securing a locking bolt of a pressure head 15 Claims, 7Drawing Figures 2 so I I 10 1 10 t I 1., I

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SHEET u UF 4 INVENTOR. CECIL R. JONES ATTORNEY APPARATUS FOR SECURINGTHE BOLTS OF THE REACTOR PRESSURE VESSEL HEAD TO THE REACTOR PRESSUREVESSEL BACKGROUND OF THE INVENTION The present invention relates to boltsecuring ap paratus, and more particularly to apparatus for securingbolts of a pressure head to a reactor pressure vessel.

A reactor pressure vessel for a boiling water nuclear power stationcontains the fuel which is the source of power. A pressure vessel headcloses the reactor pressure vessel and conventionally bolted to. theflange of the reactor pressure vessel. Approximately on an annual basis,the fuel is replaced. At each refueling, the reactor is shut down andthe pressure head is removed from the reactor pressure vessel to permitall the equipment above the reactor core to be removed for gainingaccess to the reactor fuel for replacement. After the spent fuel isreplaced with new fuel, the equipment is replaced in the pressure vesseland the pressure head is again bolted to the flange of the reactorpressure vessel.

In boiling water reactors and in pressure water reactors, the reactorpressure head must withstand an internal pressure in the range of 1,000p.s.i. 2,000 p.s.i. Therefore, the bolts and the nuts are pre-tensionedto withstand a pressure of a prescribed magnitude, which is great enoughto'resist the internal pressure in the pressure head andto provide aneffective seal between the reactor pressure vessel and the pressurehead.

Heretofore, the conventional bolt tensioning apparatus required as longas 70 hours or more for head removal time. Also, such systems increasedthe proba bility of unequal tension among the various bolts.

Patents of interest are:

Patent No. 2,866,370

Patent No. 3,015,975

Patent No. 3,168,052

PatentNo. 3,162,071

SUMMARY OF THE INVENTION Bolt. securingap:paratus with a forcetransmitting member detachably. secured at one end in threadedengagement with a securing bolt and at another end releasably securedto. a puller rod. The force transmitting memberzris split axially intotwosegments for radial displacement to facilitate the retaining of thepuller rod in engagement therewith, while rotating the forcetransmitting. member for adjustable threaded engagement with the lockingbolt without rotating the puller rod. A restraining sleeve surrounds thesplit force transmitting member and is movable axially for at timespermitting radial separation of the cylindrical force transmittingmember and at other times for securing the cylindrical forcetransmitting memberin locked threaded engagement with the puller rod formovement therewith.

The threads of the force transmitting member engaging the puller rod,are formed without a pitch. Likewise, the threads of the puller rodconfronting the force transmitting member are formed without a pitch.This feature enables the force transmitting member at times to retainthe puller rod in threaded engagement therewith while the forcetransmitting member is rotated. in adjustable threaded engagementwiththe lockingybolt without rotating the puller rod and at other times.torbe secured in locking threaded engagement with the puller rod formovement therewith.

By virtue of this arrangement, bolt securing time for the removal andreplacement of a pressure head and a reactor pressure vessel can bereduced considerably. Further, the securing and releasing between theforce transmitting member and its associated puller rod and locking boltcan be facilitated considerably and also is more rapid. Operationimpediments caused by misalignment can now be reduced.

Still another feature of the present invention is thesimultaneoussecuring of selected bolts by a plurality of bolt securingapparatus so that the entire securing process can be completed morerapidly.

A still another feature of the present invention is an apparatuspositioning device that positions each securing apparatus over itsassociated bolt and when the bolt securing process is completed, thedevice lifts the securing apparatus and advances them for positioning tothe succeeding bolt and lowers the securing apparatus for the succeedingsecuring sequence.

A still another feature is the apparatus positioning DESCRIPTION OF THEDRAWINGS FIG. 1 is a front elevation view of apparatus embodying thepresent invention illustrated in conjunction with a nut and bolt forsecuring a pressure head to a reactor pressure vessel.

FIG. 2 is an enlarged axial sectional view, partly in elevation, of theapparatus shown in FIG. 1 taken along line 2--2 of FIG. 1.

FIG. 3 is a horizontal sectional view taken along line 3-3 of FIG. 1 ofthe apparatus shown in FIG. 1.

FIG. 4 is a plan view of the apparatus shown in FIG. 1

FIG. 5 is a fragmentary developed front elevation view of the apparatuspositioning device embodying the present invention illustrated inconjunction with a plurality of the bolt securing apparatus.

FIG. 6 is a sectional view of the apparatus positioning device and boltsecuring apparatus illustrated in FIG. 5 taken along line 6-6 of FIG.Sand shown with an optical device for checking the uniformity of thetension of the bolts.

FIG. 7 is a fragmentary perspective view of a gear arrangement forrotating the bolt securing apparatus of the present invention. a

DESCRIPTION OF TI-IE PREFERRED EMBODIMENT Illustrated in FIGS. 1 and 2is a flange F 'of a reactor pressure vessel V in which vessel is storednuclear fuel. A pressure head flange F of a pressure head H is bolted tothe flange F of the reactor pressure vessel V by bolts B. Nuts N inthreaded engagement with the threads of the bolts B urge the confrontingwalls of the pressure head flange F of head H and the flange F of vesselV in sealing and locking engagement. The head of the bolt B, not shown,engages the lower wall of the flange F of the vessel v. Suitablemetallic O-rings S are interposed between the flange F and the flange Ffor sealing engagement.

The apparatus of the present invention serves to urge confronting wallsof the nut N and the flange F H of the head H away from one another sothat an operator can tighten the nut N into engagement with the flange Fof the head H. Through this action, the bolt B can be tightened to aprescribed tension, whereby a group of tightened bolts B not only meet apredetermined locking tension for each bolt B but also the lockingtension for all the bolts B are uniform.

As shown in FIGS. 1-3, the apparatus 10 comprises a cylindrical sleeve11 in which is disposed the nut N. The lower wall of the sleeve 11confronts the upper wall of the flange F of the head H surrounding thebolt B. The threaded portion of the bolt B extends above the sleeve 11into a cylindrical force transmitting body 15. According to the presentinvention, the force transmitting body 15 is split axially to form twosemi-cylindrical sections. In this manner, the force transmitting body15 through its semi-cylindrical sections is capable of radialdisplacement. 7

At its lower portion, the force transmitting body 15 is suitablyinternally threaded at 15a to engage in threaded engagement the upperthreaded portion of the bolt B. A lower retainer ring 16 and an upperretainer ring 17 urge the semi-cylindrical sections of the body 15toward one another. When the retainer rings 16 and 17 are in theposition shown in FIGS. 1 and 2, the semi-cylindrical sections of thebody 15 are retained in a close fitting relationship. When the retainerrings 16 and 17 are moved axially into the reduced outside diameterportion 15b of the body 15, the semi-cylindrical sections of the body 15are capable of radial displacement relative to one another.

At the upper portion of the cylindrical body 15 are internal threads 15Cwhich are square threads and do not have any pitch. Received by theupper portion of the body 15 in threaded engagement with the threads 15Cis a puller rod 20, which is also formed with square threads 20a that donot have any pitch. The square threads 20a of the puller rod are inthreaded engagement with the square threads 15C of the body 15.

By virtue of the above arrangement, the force transmitting body 15 andthe retainer rings 16 and 17, when the retainer rings are positioned atthe reduced diameter portion 15b of the force transmitting body 15, canbe rotated in unison about the axis of the force transmitting body forthreaded adjustment with the locking bolt B while retaining the pullerrod 20 in threaded engagement therewith without rotating the puller rod20. When the retainer rings 16 and 17 are in the position shown in FIGS.1 and 2, the force'transmitting body 15 is secured to the puller rod inlocking engagement therewith for movement therewith and for transmittinga bolt tensioning force between the puller rod 20 and the bolt B.Through this arrangement, a rapid adjustable connection and a rapiddisconnection between the force transmitting body 15 and the lockingbolt B is achieved without removing the puller rod 20 from the forcetransmitting body 15. Delay due to misalignment of parts has, therefore,been reduced.

Integrally formed with the upper end of the puller rod 20 is a piston30. The piston 30 comprises a disc shaped base 30a, which is integralwith the upper wall of the puller rod 20. A cylindrical wall 30b of thepiston 30 projects upwardly from the disc base 30a. An annular flange300 of the piston 30 projects radially from the cylindrical wall 30b. Acylindrical wall 30d of the piston 30 projects from the outer end of theflange 30c in the axial direction. 7

In sealing engagement with the piston 30 is a cylinder member 40. Asuitable O-ring seal 41 is in sealing engagement between the cylindricalwall 30d of the piston 30 and the cylinder member acting as a cylinder.Integrally formed with the inner wall of the cylinder member 40 andprojecting radially inward therefrom is an annular flange 45. Projectingdownwardly from the flange 45 and integrally formed therewith is acylindrical wall 46. A suitable O-ring seal 47 is disposed in sealingengagement with the disc base 30a of the piston 30 and the wall 46.

Depending from the cylindrical wall 46 and integrally formed therewithare axially extending, radially spaced columns 500-5041 which areintegrally formed at the feet thereof with the cylindrical sleeve 11.The columns 50a-50d are suitably concaved at the walls thereofconfronting the force transmitter body 15, but are spaced therefrom.Thus, an operator may insert a wrench therebetween for inserting intothe detents D for rotating the nut N.

The annular wall 30c of the piston 30 and the annular flange 45 aresufficiently spaced apart to define a chamber of an annularconfiguration. Fluid under pressure from a suitable source of supply ofhydraulic fluid is introduced into the chamber 55 through a flexibleconduit 56. The fluid under pressure in the chamber 55 serves to raisethe piston 30 by applying a force against the cylindrical wall 30c andserves to lower the flange 45 by applying a force against the flange 45.

The raising of the piston 30 elevates the pull rod 20. This action, inturn, transmits a force to the force transmitting body 15 for raisingthe force transmitting body 15 and, in turn, tensioning the bolt B in adirection away from the flange F of the vessel head H. At the same time,the flange 45 is lowered in the manner above described. This actioncauses the columns 50a-50 to move downwardly with the flange 45 andtransmit a downwardly directed force through the connector sleeve 11.The connector sleeve 1 1, in turn, urges the flange F of the head I-Idownwardly away from the nut N. An operator can easily turn the nut Nthrough a suitable tool for tightening the same against the flange F ofthe vessel head H by inserting a wrench in the accesses between thecolumns 50a-50d. The wrench is received by the nut detents D forrotating the nut N. The apparatus 10 as illustrated in FIG. 2 is in thebolt tensioned position for rotating the nut N.

When the supply of hydraulic fluid under pressure in the chamber 55 isinterrupted or discontinued through a suitable shutoff valve, theconnector sleeve 1 l returns the flange 45 to its initial position. Thepiston 30 also returns towards its unloaded position through theinterruption of the fluid under pressure into the chamber 55. At thistime, the sleeves 16 and 17 are moved axially to the reduced diameterportion 15b of the force transmitting body. The semi-cylindricalsections of the force transmitting body 15 are then moved radiallyoutward to disconnect the body 15 from the locking bolt B. The pullerrod 20 remains in threaded engagement with the body 15. Thus, the bolt Bis now disconnected from the apparatus so that the apparatus 10 can bemoved angularly for the succeeding bolt securing operation. An annularstop member 60 with O-ring seal 63 is bolted to member 40.

A conventional extensometer 70 is fixed to the bolt B for measuring thebolt elongation and may be of the type disclosed in US. Pat. No.3,015,975. Formed in the force transmitting body is an opening 71aligned with the extensometer 70 to enable an operator to read the dialindicator of the extensometer 70. The extensometer 70 is attachedrespectively to each bolt B and remains attached to each bolt Brespectively during the entire bolt tensioning operation for improvedaccuracy. Through this arrangement, the. tension on each bolt B is readindividually and can be read individually for each bolt B during theentire bolt tensioning operation for the flanges F and F to be certainof uniformity of tension among all the bolts B and that each bolt Bmeets its prescribed minimum requirements for the safety of the nuclearpower plant.

According tothe present invention, the flange F of the pressure head His secured to the flange F of the vessel V by securing a preselectednumber of bolts B and associated nuts N simultaneously. In the exemplaryembodiment, a plurality of bolt securing apparatus 10 (FIGS. 5 and 6)are employed simultaneously, which serve to tension, for example, everyfourth locking bolt B in the manner above described and to unseat theassociated nutN from the flange F H in the manner above described. Thus,it takes four sequential operations, in the exemplary embodiment, tobolt the flange F to the flange f During each cycle, one-fourth of thebolts B are secured. The apparatus 10 are angularly spaced in equaldistances from one another about the axis of the head H and the vessel Vand move in a circular path about the axis of the head H and the vesselV to advance to successive bolts during each succeeding bolt securingcycle or sequence. Each apparatus 10 is angu larly spaced from itsadjacent apparatus 10 by an angular distance equal to the angulardistance between five successive bolts Thus, each apparatus 10 advancesto four successive bolts B during the four sequential bolt securingoperations.

For facilitating the placement of the pressure head flange F H on thevessel flange Fv, a preselected number of bolts B have a removableconical cap 80 seated thereon for guiding and indexing the location ofthe apparatus l0 with'respect to the location of the locking bolts B. Inthe preferred embodiment, a conical cap 80 is seated on every fourthlocking bolt B. The caps 80 are received by openings in a rotatableannular plate 94 that is fixed to all of the cylindrical walls 46 of theap-, paratus 10 through a platform 92. After. the initial positioning ofthe apparatus 10 on the flange F the conical caps 80 are removed. Duringeach bolt securing cycle or sequence, each extensometer 70 will remainwith its associated bolt B during the entire bolt tensioning operation.After all the bolts are secured, the extensometers will be detached. Inthis manner, there is assurance that each bolt B will be properlytensioned and all the bolts B are of equal tension.

In order to advance each bolt securing apparatus 10 to the succeedingbolt over a circular path, each apparatus 10 is elevated at thecompletion of each cycle and lowered at the beginning of each successivecycle. Toward this end, a suitable hydraulic system is provided witheach apparatus 10. Depending from each hydraulic system 90 is a shaft91. The shaft 91 is elevated or raised in a well-known manner by theassociated hydraulic system 90.

At the distal end of each shaft 91 is fixed an elevator platform 92 anda horizontal plate 93, which is fixed to the cylindrical wall 46 of eachof the apparatus 10. Thus, the raising of the pistons, not shown, in thehydraulic systems 90 raises the shafts 91. In turn, the shafts 91 raisethe elevator platform 92 and the horizontal plate 93. When the elevatorplatform 92 and the horizontal plate 93 are fully raised, each apparatus10 is elevated to the position shown in dotted lines in FIG. 6. When theelevator platform 92 and the annular plate 93 are fully lowered, eachapparatus 10 is lowered to the position shown in solid lines in FIG. 6.

While each of the apparatus 10 is in the fully elevated position, allthe apparatus 10 are rotated over a circular path to the succeeding boltB at the beginning of each bolt securing cycle or sequence. For thispurpose, the horizontal plate 93 is fixed to the cylindrical walls 46 ofthe apparatus 10. To rotate the apparatus 10 to successive angularpositions, each apparatus 10 has a suitable drive arrangement whichincludes an electrically operated drive motor 101, a pinion gear 102, agear reducer 103, and rack 105. The apparatus 10 and drive 100 are fixedto a movable annular plate 94. The gear rack is fixed to a stationaryannular plate 95. The plate 95 is fixed to the pressure head H. Suitablebearings, not shown, are interposed between the annular plate 94 and thestationary plate 95 so that the annular plate 94 moves relative to theplate 95 for rotating the apparatus 10 over a circular path. An operatorenergizes the electrical motor 101 mounted on the plate 94 by operatinga switch which meshes with the stationary rack 105, thereby rotating theplate 94 with the apparatus 10.

A cylindrical container is mounted on the pres sure head I-I adjacenteach apparatus 10 for storing locking bolts, nuts, washers, and thelike. By virtue of rotating each apparatus 10 to the succeeding bolt tobe secured by means of the drive. arrangement 100, the need for anoverhead cranefor sequential positioning of the apparatus 10 has beenobviated.

For the safety of the nuclear power plant, it is essential that all thebolts B be uniformly tensioned. Toward this end, an optical system 109is magnetically attached to the pressure head by means of an annularmagnetic attaching device 111.An optical aligning device 112 with atransit 113 sights a prearranged marker on an overhead scale 1 14attached to the edge of the reactor well. If all the bolts B areuniformly tensioned, then the flange F of the pressure head H will besubstantially flat and the optical aligning device 112 will have itstransit 113 sighted for alignment with the prearranged marker. Shouldthe bolts B not be uniformly tensioned, then the flange F of thepressure head H will have a slight deviation relative to a horizontalplane. This will result in the transit 113 being sighted slightly offthe prearranged marker. Further, bolt tensioning adjustment will be madefor uniformity in each discrete bolt B. Thus, initial uniform test ismade with the extensometers 70 and the final uniformity test is madewith the optical system 109. It is apparent that perfect uniformity inthe bolt tensioning will provide the ideal sealing with the o-rings Sand between the flange F and the flange F I claim:

1. Apparatus for tensioning a bolt and unseating a nut in threadedengagement with the bolt comprising:

a sleeve adapted to apply a force against a wall on which the nut isseated and adapted for receiving the nut;

a cylindrical force transmitting body having one end thereof in threadedengagement with a portion of the bolt projecting beyond the nut, saidbody being separated in the axial direction for radial displacement;

a puller rod attached to the other end of said cylindrical forcetransmitting body, and

hydraulic means connected to said puller rod for applying a force in oneaxial direction for tensioning the bolt and connected to said sleeve forapplying an axial force against the wall on which the nut is seated inan opposite direction. v

2. Apparatus as claimed in claim 1 wherein said cylindrical forcetransmitting body and said puller rod are in threaded engagement bymeans of pitchless threads.

3. Apparatus as claimed in claim 1 wherein said cylindrical forcetransmitting body and said puller rod are in threaded engagement bymeans of square threads.

4. Apparatus as claimed in claim 2 wherein said cylindrical forcetransmitting body is separated in the axial direction to formsemi-cylindrical sections.

5. Apparatus as claimed in claim 4 andcomprising a retainer ringsurrounding said cylindrical force transmitting body for holdingtogether said cylindrical force transmitting body.

6. Apparatus as claimed in claim 5 wherein said cylindrical forcetransmitting body has a reduced outer diameter along a portion thereofand said retainer ring is slidable to the reduced diameter portion ofthe force transmitting body to enable radial displacement thereof and isslidable to the increased diameter portion of the force transmittingbody for urging together the cylindrical force transmitting body.

7. Apparatus as claimed in claim 5 wherein said hydraulic means includecolumns axially disposed and radially spaced that extend along the outerwall of the cylindrical force transmitting body and are connected at thefeet thereof to said sleeve for transmitting a force through said sleevefor application against a wall on which the nut is seated.

8. Arrangement for securing confronting flanges of annularconfigurations through bolts and nuts comprising:

a plurality of apparatus for tensioning bolts, respectively, andunseating, respectively, nuts threaded engagement with respective bolts,said apparatus being disposed at equal angular distances about the axisof said confronting flanges;

elevating means engaging said apparatus for raising and lowering saidapparatus, and

drive means connected to said apparatus for rotating said apparatusabout said axis for advancing said apparatus in a circular path.

9. Arrangement as claimed in claim 8 wherein a preselected number ofbolts and nuts in threaded engagement are disposed between successiveapparatus, said apparatus simultaneously tension associated bolts andsimultaneously unseat associated nuts, said drive means advance insequence said apparatus simultaneously to successive bolts and nut inthreaded engagement.

10. Arrangement as claimed in claim 8 and comprising a extensometermounted on each bolt being tensioned during the entire period of timesuch bolts are being tensioned for checking for prescribed tension oneach bolt, respectively, and for uniform tension between all of thebolts.

1 l. Arrangement as claimed in claim 8 and comprising detachable guidemeans mounted on each of preselected bolts for guiding the location ofthe respective apparatus relative to the location of the associatedbolts.

l2. Arrangement as claimed in claim 9 wherein said elevating meansraises said apparatus at the completion of each bolt securing sequenceand said drive means rotate said apparatus while in the raised positionprior to the beginning of the succeeding bolt securing sequence.-

13. Arrangement as claimed in claim 8 and comprising container meansadjacent said apparatus for storing removed bolts and nuts.

14. Arrangement as claimed in claim 9 and comprising optical sightingmeans mounted on said confronting flanges for sighting a preselectedmarker to test for uniformity of tension of said bolts.

15. Arrangement as claimed in claim 14 wherein said confronting flangesdeviate from a horizontal plane when the tensioning of said bolts is notuniform to misalign said optical sighting means from said marker andwherein said confronting flanges is flat when the tensioning of saidbolts is uniform to align said optical sighting means with said marker.

1. Apparatus for tensioning a bolt and unseating a nut in threadedengagement with the bolt comprising: a sleeve adapted to apply a forceagainst a wall on which the nut is seated and adapted for receiving thenut; a cylindrical force transmitting body having one end thereof inthreaded engagement with a portion of the bolt projecting beyond thenut, said body being separated in the axial direction for radialdisplacement; a puller rod attached to the other end of said cylindricalforce transmitting body, and hydraulic means connected to said pullerrod for applying a force in one axial direction for tensioning the boltand connected to said sleeve for applying an axial force against thewall on which the nut is seated in an opposite directIon.
 2. Apparatusas claimed in claim 1 wherein said cylindrical force transmitting bodyand said puller rod are in threaded engagement by means of pitchlessthreads.
 3. Apparatus as claimed in claim 1 wherein said cylindricalforce transmitting body and said puller rod are in threaded engagementby means of square threads.
 4. Apparatus as claimed in claim 2 whereinsaid cylindrical force transmitting body is separated in the axialdirection to form semi-cylindrical sections.
 5. Apparatus as claimed inclaim 4 and comprising a retainer ring surrounding said cylindricalforce transmitting body for holding together said cylindrical forcetransmitting body.
 6. Apparatus as claimed in claim 5 wherein saidcylindrical force transmitting body has a reduced outer diameter along aportion thereof and said retainer ring is slidable to the reduceddiameter portion of the force transmitting body to enable radialdisplacement thereof and is slidable to the increased diameter portionof the force transmitting body for urging together the cylindrical forcetransmitting body.
 7. Apparatus as claimed in claim 5 wherein saidhydraulic means include columns axially disposed and radially spacedthat extend along the outer wall of the cylindrical force transmittingbody and are connected at the feet thereof to said sleeve fortransmitting a force through said sleeve for application against a wallon which the nut is seated.
 8. Arrangement for securing confrontingflanges of annular configurations through bolts and nuts comprising: aplurality of apparatus for tensioning bolts, respectively, andunseating, respectively, nuts in threaded engagement with respectivebolts, said apparatus being disposed at equal angular distances aboutthe axis of said confronting flanges; elevating means engaging saidapparatus for raising and lowering said apparatus, and drive meansconnected to said apparatus for rotating said apparatus about said axisfor advancing said apparatus in a circular path.
 9. Arrangement asclaimed in claim 8 wherein a preselected number of bolts and nuts inthreaded engagement are disposed between successive apparatus, saidapparatus simultaneously tension associated bolts and simultaneouslyunseat associated nuts, said drive means advance in sequence saidapparatus simultaneously to successive bolts and nut in threadedengagement.
 10. Arrangement as claimed in claim 8 and comprising aextensometer mounted on each bolt being tensioned during the entireperiod of time such bolts are being tensioned for checking forprescribed tension on each bolt, respectively, and for uniform tensionbetween all of the bolts.
 11. Arrangement as claimed in claim 8 andcomprising detachable guide means mounted on each of preselected boltsfor guiding the location of the respective apparatus relative to thelocation of the associated bolts.
 12. Arrangement as claimed in claim 9wherein said elevating means raises said apparatus at the completion ofeach bolt securing sequence and said drive means rotate said apparatuswhile in the raised position prior to the beginning of the succeedingbolt securing sequence.
 13. Arrangement as claimed in claim 8 andcomprising container means adjacent said apparatus for storing removedbolts and nuts.
 14. Arrangement as claimed in claim 9 and comprisingoptical sighting means mounted on said confronting flanges for sightinga preselected marker to test for uniformity of tension of said bolts.15. Arrangement as claimed in claim 14 wherein said confronting flangesdeviate from a horizontal plane when the tensioning of said bolts is notuniform to misalign said optical sighting means from said marker andwherein said confronting flanges is flat when the tensioning of saidbolts is uniform to align said optical sighting means with said marker.